Process for the production of metals by smelting compounds thereof



March 23, 1937. F N R 2,074,726

PROCESS FOR THE PRODUCTION OF METALS BY S MELTING COMPOUNDS THEREOF Filed Jan. 2, 1935 COOLING WATER D/LUFNE GAS TV EUULI/YG WATER Patented Mar. 23, x 1937 UNITED ST ES PATENT OFFICE raocnss roa 'rns raonuc'rron or METALS BY SMELTING COMPOUNDS THEREOF Fritz Hansgirg, Radenthein, Austria, asslgnor to American Magnesium Metals Corporation, Pittsburgh, Pa., a corporation of Delaware Application January 2, 1935, Serlal'No. 33

- In Austria July 27, 1934 3 Claims.

This invention-relates to the production of metals by smelting compounds thereof, particularly oxidlc compounds with the aid of a re-- ducing agent.

Objects of the inventionare to provide a method for the smelting of metals which can be carried on in a perfectly continuous operation; also to devise a smelting method permitting of a practically perfect control of the reduction temperature, and condensation conditions; also to .provide a method in which no-residue or slag is left behinddn the reductionchamber.

The'invention refers in particular to smelting processes practiced by the heating of an intimate mixture of the material to be reduced with a reducing agent, especially with a carbonaceous reducing agent, to temperatures above the boiling point of the metal to be recovered, the temperature being appropriately chosen in dependence on the working pressure used (reduced pressure,

ply of heat that the giving oi! of the gaseous products of reaction from the charge approxi- 35 mately keeps pace with the rate of feed ofthe latter, so that ng of the charge in the reduction chamber is substantially avoided. According to a preferred embodiment the charging is effected with material in the shape of small 40 briquettes which are thrown into the highly heated reduction chamber. The briquettes are molded, for instance, from a mixture of pulverized material containing metallic oxld and finely divided carbonaceous material, with a binding 4 agent of a nature to become carbonized under heat (for instance tar pitch), and baked in the usual manner or introduced into the reduction chamber in a non-baked state. The present invention aims at enabling proc- 50 esses of this nature to be practiced simply and reliably and accomplishes this end with utilizationiof indirect resistance furnaces working purely on-the principle of resistance heating'under circumstances in which the charge participates 55 in the carrying of the current only to an extremebe used with advantage.

ly slight extent, it at all. According to the invention, the small individual portions of the charge are caused to drop upon a loosely heaped bed of granular material of high resistance which is heated in the usual manner with the 5 aid of current conducting electrodes. Slack coal-resistance furnaces of the known type can The bed of slack coal radiates heat to the walls of the furnace, so that the whole of the interior of the furnace is heated 10 r to a uniform temperature.

The portions of the charge, forexample briquettes, are dropped on to this slack coal bed, as described, continuously but with regularly interposed intervals and thus in this sense intermittently, and assume by direct 15 'contact with the highly heated resistance mass.

the temperature of this latter, being thereby at once converted into vapors and gases.

That the briquettes dropped into the furnace participate only to a very slight extent in the 20 v carrying of the current is shown by the fact that the current consumption of the furnace remains perfectly. constant, after the attainment of the maximum temperature, whether briquettes are introduced or not. q

Apparatus suitable for the carrying out of the process is shown in the amompanying drawing, 7 in side elevation and partly in vertical section.

At the bottom of the electric furnace i there is heaped granular resistance material it, for ex- 3 ample slack coal, in which the ends of the current conducting electrodes l2, I! are buried.

Into the top of the furnace there issues a tube 2 the upper end of which is connected to a bucket conveyor which consists of a disk 4 provided with buckets 3 and projecting partly into a briquette storage container 5. The briquettes dropping from the buckets into the tube 2 are required to traverse a lock chamber which is equipped with two plate-shaped closure members i and 'I. These 40 closure members are actuated by means of two systemsof levers I and 9 which are so controlled by eccentrics Ill and l I that the one closure member intercepts the passage before the other begins to open. Tube 2 is, moreover, provided with a gas inlet pipe is. The discharge opening of the furnace l is lined with a water-cooled jacket I4 and is connected by tube IS with a filtering apparatus l6. Coaxially within the discharge opening there is arranged a water-cooled cylinder II. The casing of this cylinder is provided with nozzles It for the escape of cooling and diluting gas.

From the bucket conveyor there drops at regular intervals one briquette at-a time, which is arrested by the plate 6. As soon as the plate 1 reaches the position of closure the plate S is retractcd and the briquette allowed to drop on to the plate I which in its turn begins to be retracted 5 as soon as the plate 6 resumes the position of closure. The briquette then drops on to the highly heated slack coal bed l3 with violent evolution of the vaporous and gaseous reaction products. A stream of non-oxidizing gas is intro- 10 duced through pipe is to serve as a carrier and at the same time to prevent the gases and vapors evolved within the furnace I from rising through tube 2. The latter pass out through the discharge opening where they are diluted and rapidly cooled oi! by a cold inert or reducing gas escaping from the nozzles I I. In the filtering plant Ii the metallic dust is separated out while the gas is conducted off and returned into circulation after suitable cleaning.

The charging is so regulated, as to nature and rate of feed, that the interval'between the admission of one briquette and the next into the furnace approximately corresponds to the time required for the evolution of the vaporous and gaseous reaction products of one briquette. In this manner any amassing of the charge in the furnace is avoided.

Y What I claim is:

l. A process for the production of magnesium,

which comprises forming into detached uniformly small compacted bodies a mixture of a reducible magnesium compound and of a solid reducing agent in an amount suflicient for enecting reduction of the magnesium compound without the 3 use of a co-operative gaseous reducing agent, causing said detached bodies to drop one by one at regular intervals on to a body of non-metallic resistance material loosely heaped on the bottom of a closed electric furnace and directly heated to above the bofling point of magnesium, to liberate and vaporize the magnesium content of each detached body so suddenly as to avoid any substantial accumulation of the charge in the reduction chamber without the charge Substantially participating in the carrying of the current; thereafter passing the evolved magnesium vapor into a condenser and cooling it to condensation point.

2. A process for the production of magnesium, which comprises forming into detached uniformly small compacted bodies a mixture of a reducible magnesium compound and of a solid reducing agent in an amount suilicient for effecting reduction of the magnesium compound-without the use of a co-operative gaseous reducing agent, causing said detached bodies to drop one by one at regular intervals on to a body of granular slack coal loosely heaped on the bottom of a closed electric furnace and directly heated to above the boiling point of magnesium, to liberate and vaporize the magnesium content of each detached body so suddenly as to avoid any substantial accumulation of the charge in the reduction chamber without the charge substantially participating in the carrying of the current; thereafter passing the evolved magnesium vapor into a condenser and cooling it to condensation point.

3. A process for the production of magnesium which comprises forming into detached unifonnly small compacted bodies a mixture of a reducible magnesium compound and of a solid carbonaceous reducing agent in an amount suflicient for effecting reduction of the magnesium compound without the use of a co-operative gaseous reducing agent, causing said detached bodies to drop one by one at regular intervals on to a body of non-metallic resistance material loosely heaped on the bottom of a closed electric furnace and directly heated to above the boiling point of magnesium, to liberate and vaporize the magnesium content of each detached body so suddenly as to avoid any substantial accumulation of the charge in the reduction chamber without the charge substantially participating in the carrying of the current; thereafter passing the evolved magnesium vapor into a condenser and cooling it to condensation point.

FRITZ HANSGmG. 

